Arseno-azo compounds and process of making same.



UNITED STATES PATENT OFFICE.

PAUL EHB-LICH AND PAUL KARE ER, OF FRANKFORT-ON-THE-MAIN, GERMANY,

ASSIGNORS TO FARIBWERKE VORM. MEIS'IER LUCIUS & BRUNING, OF,H6CHST- ON-THE-MAIN, GERMANY, A CORPORATION OF GERMANY.

ABSENO-AZO CClMPOUNDS AND PROCESS OF MAKING SAME.

No Drawing To all whom it may concern Be it known that we, PAUL EHRLICH, M. D., rofessor of medicine, and PAUL I ARRER, l1. D., chemist, citizens of the Empire of Germany and Republic of Switzerland, respectively, residing at F rankfort-onthe-Main, Germany, have invented certain new and useful Improvements in Arseno- Azo Compounds and Processes of Making Same, of which the following is a specification.

We have found that azo d estuifs containing an arseno group -As= which were hitherto unknown can be produced by re ducing azo dyestufls containing the arsinic acid group A,sO,H by means of hypophosphorous acid., This reducing agent does not alter the azo group, but only attacks the arsinic acid group so as to form the corresponding arseno compound. These new arseno-azo dyestufis are colored compounds dissolving in alkalis and they are of great value for therapeutical purposes; the

can be converted into starting azo dyestu s Specification of Letters Patent.

Patented Dec. 15, 1914.

Application filed February 2, 1914. Serial No. 816,097.

C -N N n y (in (in are added 50 grams of hydrophosphorous acid of 35 per cent. strength and the mixture is kept boiling for hour while well stirring. The red dyestufi which separates is filtered off and washed with water; it is soluble in alkalis with a red color and corresponds to the formula Example II: 3 grams of the dyestuff produced from m-amindphenylarsinic acid and 2.3.6-aminonaphthalene disulfonic acid,

NH, SO|H are dissolved in 50 cc. of hypophosphorous N=N acid and heated to boiling. After a. short time the arseno-azo dyestuif BChBa A: 2: A5 Ems N 6 NH. 50; J

s0- soln separates as a brownish-red powder which is soluble in alkalis with a red color.

Example III: 10 grams of'the dyestufi produced from; diazoatoxyl and 1.8.3.6-

aminonaphtholdisulfonic acid and having the formula are dissolved in 100 cc. of hypophosphorous acid of 25 per cent. strength and heated to boiling. The dyestufi' dissolves and the difficultly soluble arseno compound separates at once. This compound, when dry, forms a dark powder with a metallic luster and dissolves in Water and alkalis to a violent H 03 AS solution. It corresponds to the formula 30,5 As SOQH Having now described our invention What we claim is:

1. As new products, azo compounds con- 50,3 being a dark powder, dissolving in caustic soda-lye with a violet color and being insoluble in alcohol, ligroin and ether.

3. As a new process, the treatment of amcompounds containing an arsinic acid group with 'hypophosphorous acid.

In testimony whereof, we afiix our signatures in presence of two Witnesses.

PAUL EHRLICH. PAUL KARRER.

\Vitnesses 2 JEAN GRUND, CARL GRUND.

It is hereby certified that in Letters Patent No. 1,120,700, granted December 15,

1914, upon the application of Paul Ehrlich and Paul Karrer, of Frankfort-on-the- Main, Germany for an improvement in Arscno-Azo Compounds and Processes of Making Sa1ne,ei'roi-s appear in the printed specification requiring correction as follows: Page 2, line 18, for the word violent" read violet; same page, line 36, for

the word dyestufls read compounds, and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 4th day of May, A. D., 1915.

[SEAL] R. F. VVHITEHEAD Acting Commissioner of Patents. 

